Rear Engine Modified Roadster Build

[hitz]

I tested the roll over valve I had purchased(without the tank in the car) and found that it flowed fuel from about 20 deg to about 160 deg. I bent a piece of tubing around the rear edge of the the tank like someone on this forum suggested and tested it. It would leak a little fuel as you rotated the tank but not flow when you stopped turning the tank. Of course if you laid it on the back of the tank it would just run out.

[hitz]

I think a roll over valve with a light coil spring pushing on a nylon ball would work in all positions. Anybody making these?

Harv

[maguromic]

Harv, Fuel Safe makes a spring loaded roll over /vent valve.  It didn’t work for us as it was too small to work with the dry break.  Both ATL and Fuel Safe makes a nylon ball that is compatible with gas and alcohol / methanol (though not nitro).  We went with the Fuel Safe ball, as it was a bigger unit. Tony

[saltfever]

. . .  We went with the Fuel Safe ball, as it was a bigger unit. Tony

Just to clarify . . . you are going to incorporate your puck design into the Fuel safe? 

[maguromic]

Yes, we are using the puck system. We have built a complete new roll over /vent valve of our own design.  This is the ball we are using with the puck system.  Tony

[bharmon77]

Your front anti roll bar idea is neat. I fought that battle and finaly ended up with a compact conventional design but your design would have fit much better!

BHarmon
H/BFL 7077

[saltfever]

Tony: Back in post #55 you showed a pic of your air box. You mentioned your were going to do some CFD anaylsis on the flow. Did you ever get a chance to do that? Results?

It has a unique, NURBS look to it. It is a solid model or a lofted and surfaced wire-frame? Are you going to NC it out of billet or do a sheet metal fab? Sorry for so many questions but this is a fasinating build and a very rare opportunity to see the design proccess taking place. 

[maguromic]

Bharmon , Thanks for the compliment. Some of this build is dictated by what we have on the shelf.  Since this is a budget build we try to use stuff we already have.  The ARB we are using is off a Reynard Indy car and run about $75 or less on the used race car parts market.  After figuring out the mounting locations I just designed the front bar that bolts to the existing ARB. Tony

Reynard ARB before modifying.

[maguromic]

Elon,  I haven’t had a chance to do the CFD on this yet and its on the to do list.  NURBS does make life a lot easier.  Once I figure out everything I need the part will be done on a CNC.  But I still need to finish the head first though.  My ideal plenum needs to hold enough air for  the engine at its peak and be able to distribute it evenly without much pressure drop.  This type of plenum is not my idea. When I started looking for plenum designs I looked at what the LMP cars were running and first noticed the Audi version and also saw that other forms of racing are using very similar designs for their optimization.

Keep the questions coming, I have no secrets (maybe some ) in racing.

From the Audi web site.


Ford Rally car Engine Plenum.

[saltfever]

Here is a pic of a Ferrari F-40. A classic example of Bernoulli at his finest. (Decreasing radius air box) The splitting of the intercoolers for packaging reasons is another nice idea. What LSR car doesn't care about packaging! 

My apologies if others consider this "thread drift". Since Tony shared his air box design I thought another interesting idea might be acceptable.  

[maguromic]

This is the preliminary bell-housing scheme.  I will still need to fine-tune everything.  Originally we were going to weld a bell-housing together, but after looking at what is available we were able to find a unit by Quicktime that could be modified.  Due to ground clearance issues we went with a 110-tooth flywheel and clutch combo and had to flatten the bottom of the bell-housing to make it all work.

To clear the reverse mount starter it would have taken a major hole in the bell-housing and  instead we used an adapter to mate the starter directly to the mid-plate.  This will eliminate tolerance and weld deflection issues with the bell-housing and makes “tuning” the starter adjustments to the ring gear straightforward and reliable.

This particular mid-plate is designed for the GMC 6 and the Chevy / Aurora IRL engine.  We also have one with a SBC, BBC and V4F pattern.

I want to thank Quicktime for sending us a drawing of their bell housing to work with. Tony

[maguromic]

Forgot to add:  For the bell-housing support, I am thinking of some non-structural support just to keep it approximately aligned while the engine is being installed.  The long input shaft of the trans axle has the same issue.  For this I would like to use some type of bushing in the clutch release sleeve maybe delrin or Teflon – it wont touch in service, but needs not to melt).  I hate battles with trying to get input shafts to align, and this one would be a tough one without some forethought here.  The starter will come in and out easily and wont need this type of treatment (hopefully).  Tony

[saltfever]

Can you temporarily install 2 or 3 studs into the transaxle? (long enough to ensure input shaft engagement into the clutch) They would act as guides as everything is slipped together. Then remove them, one at a time, as you replace with bolts. Can't tell if you have the clearance to remove the studs, though.   Great pictures.   

[maguromic]

That’s a good idea, but unfortunately it wont work with me.  My imput shaft is about 18” long from the trans axle flange and also there is another housing that bolts to the trans axle flange and to the back of the bell-housing.  One positive thing though is from my experience; the long imput shafts are very good at softening engine power pulses and improving traction.    Next on the list is to design the dry sump tank to fit its location.  Tony

[saltfever]

Yikes! 18" . . . but great for the salt. 
What oil filter are you going to run and where located? Incorporated into the tank?